-# libsyntax2.0
+# Rust Analyzer
-[](https://gitter.im/libsyntax2/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
-[](https://travis-ci.org/matklad/libsyntax2)
-[](https://ci.appveyor.com/project/matklad/libsyntax2/branch/master)
+[](https://travis-ci.org/matklad/rust-analyzer)
+[](https://ci.appveyor.com/project/matklad/rust-analyzer/branch/master)
+Rust Analyzer is an **experimental** modular compiler frontend for the
+Rust language, which aims to lay a foundation for excellent IDE
+support.
-libsyntax2.0 is an **experimental** implementation of the corresponding [RFC](https://github.com/rust-lang/rfcs/pull/2256).
+It doesn't implement much of compiler functionality yet, but the
+white-space preserving Rust parser works, and there are significant
+chunks of overall architecture (indexing, on-demand & lazy
+computation, snapshotable world view) in place. Some basic IDE
+functionality is provided via a language server.
-See [`docs`](./docs) folder to learn how libsyntax2 works, and check
-[`CONTRIBUTING.md`](./CONTRIBUTING.md) if you want to contribute!
+## Quick Start
+
+Rust analyzer builds on stable Rust >= 1.29.0.
+
+```
+# run tests
+$ cargo test
+
+# show syntax tree of a Rust file
+$ cargo run --package ra_cli parse < crates/ra_syntax/src/lib.rs
+
+# show symbols of a Rust file
+$ cargo run --package ra_cli symbols < crates/ra_syntax/src/lib.rs
+```
+
+To try out the language server, see [these
+instructions](./editors/README.md). Please note that the server is not
+ready for general use yet. If you are looking for a Rust IDE that
+works, use [IntelliJ
+Rust](https://github.com/intellij-rust/intellij-rust) or
+[RLS](https://github.com/rust-lang-nursery/rls). That being said, the
+basic stuff works, and rust analyzer is developed in the rust analyzer
+powered editor.
+
+
+## Current Status and Plans
+
+Rust analyzer aims to fill the same niche as the official [Rust
+Language Server](https://github.com/rust-lang-nursery/rls), but uses a
+significantly different architecture. More details can be found [in
+this
+thread](https://internals.rust-lang.org/t/2019-strategy-for-rustc-and-the-rls/8361),
+but the core issue is that RLS works in the "wait until user stops
+typing, run the build process, save the results of the analysis" mode,
+which arguably is the wrong foundation for IDE.
+
+Rust Analyzer is a hobby project at the moment, there's exactly zero
+guarantees that it becomes production-ready one day.
+
+The near/mid term plan is to work independently of the main rustc
+compiler and implement at least simplistic versions of name
+resolution, macro expansion and type inference. The purpose is two
+fold:
+
+* to quickly bootstrap usable and useful language server: solution
+ that covers 80% of Rust code will be useful for IDEs, and will be
+ vastly simpler than 100% solution.
+
+* to understand how the consumer-side of compiler API should look like
+ (especially it's on-demand aspects). If you have
+ `get_expression_type` function, you can write a ton of purely-IDE
+ features on top of it, even if the function is only partially
+ correct. Plugin in the precise function afterwards should just make
+ IDE features more reliable.
+
+The long term plan is to merge with the mainline rustc compiler,
+probably around the HIR boundary? That is, use rust analyzer for
+parsing, macro expansion and related bits of name resolution, but
+leave the rest (including type inference and trait selection) to the
+existing rustc.
+
+## Code Walk-Through
+
+### `crates/ra_syntax`
+
+Rust syntax tree structure and parser. See
+[RFC](https://github.com/rust-lang/rfcs/pull/2256) for some design
+notes.
+
+- `yellow`, red/green syntax tree, heavily inspired [by this](https://github.com/apple/swift/tree/ab68f0d4cbf99cdfa672f8ffe18e433fddc8b371/lib/Syntax)
+- `grammar`, the actual parser
+- `parser_api/parser_impl` bridges the tree-agnostic parser from `grammar` with `yellow` trees
+- `grammar.ron` RON description of the grammar, which is used to
+ generate `syntax_kinds` and `ast` modules.
+- `algo`: generic tree algorithms, including `walk` for O(1) stack
+ space tree traversal (this is cool) and `visit` for type-driven
+ visiting the nodes (this is double plus cool, if you understand how
+ `Visitor` works, you understand rust-analyzer).
+
+
+### `crates/ra_editor`
+
+All IDE features which can be implemented if you only have access to a
+single file. `ra_editor` could be used to enhance editing of Rust code
+without the need to fiddle with build-systems, file
+synchronization and such.
+
+In a sense, `ra_editor` is just a bunch of pure functions which take a
+syntax tree as an input.
+
+### `crates/salsa`
+
+An implementation of red-green incremental compilation algorithm from
+rust compiler. It makes all rust-analyzer features on-demand.
+
+
+### `crates/ra_analysis`
+
+A stateful library for analyzing many Rust files as they change.
+`AnalysisHost` is a mutable entity (clojure's atom) which holds
+current state, incorporates changes and handles out `Analysis` --- an
+immutable consistent snapshot of world state at a point in time, which
+actually powers analysis.
+
+
+### `crates/ra_lsp_server`
+
+An LSP implementation which uses `ra_analysis` for managing state and
+`ra_editor` for actually doing useful stuff.
+
+
+### `crates/cli`
+
+A CLI interface to libsyntax
+
+### `crate/tools`
+
+Code-gen tasks, used to develop rust-analyzer:
+
+- `cargo gen-kinds` -- generate `ast` and `syntax_kinds`
+- `cargo gen-tests` -- collect inline tests from grammar
+- `cargo install-code` -- build and install VS Code extension and server
+
+### `editors/code`
+
+VS Code plugin
+
+
+## Performance
+
+Non-incremental, but seems pretty fast:
+
+```
+$ cargo build --release --package ra_cli
+$ wc -l ~/projects/rust/src/libsyntax/parse/parser.rs
+7546 /home/matklad/projects/rust/src/libsyntax/parse/parser.rs
+$ ./target/release/ra_cli parse < ~/projects/rust/src/libsyntax/parse/parser.rs --no-dump > /dev/null
+parsing: 21.067065ms
+```
+
+## Getting in touch
+
+@matklad can be found at Rust
+[discord](https://discordapp.com/invite/rust-lang), in
+#ides-and-editors.
## License
-libsyntax2 is primarily distributed under the terms of both the MIT license
-and the Apache License (Version 2.0).
+Rust analyzer is primarily distributed under the terms of both the MIT
+license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT for details.
projects / rust.git / blobdiff